Deborah Norville on the Story of a Mother's Quest for Justice That Inspired Her New True Crime Lifetime Movie

Inside Edition Anchor Deborah Norville is one of the executive producers of the new Lifetime movie, “The Long Island Serial Killer: A Mother’s Hunt for Justice.”

Inside Edition Anchor Deborah Norville is one of the executive producers of the new Lifetime movie, “The Long Island Serial Killer: A Mother’s Hunt for Justice.” The film tells the story of Mari Gilbert, portrayed by Kim Delaney, who pushed police in Long Island, New York to search for her missing daughter. In so doing, authorities ended up discovering the bodies of several victims of a serial killer.

“I think the thing that I take away from this movie is that all of us have power," Norville said. "If it weren't for this woman in real life named Mari Gilbert, as many as 16 murdered women's bodies would have never been found."

It all started when Mari's daughter, Shannan, didn't come home from a date in the spring of 2010. Shannan was in her 20s and working as an escort. "Now, she saw her mom that evening. In fact, saw her just before she was leaving for the date," Norville said. "So the timeline was established, but she never came home. There was a mysterious call to the police by Shannan saying, 'They're trying to kill me.'Then the line went dead. She disappeared. They looked and looked, but they didn't find her."

A week after Shannan's disappearance, Mari received a call from a man who said, "I tried to help your daughter, but she wouldn't listen." Mari tried to ask questions, but the line went dead. 

"Mari Gilbert went to the police and she said, 'My daughter is missing. She disappeared.' They said, 'Oh, when was she last seen?'" Norville said. When Mari said Shannan had been on a date, police asked if she was a sex worker.

"So the cops were not interested because this woman was, in their mind, a marginalized person," Norville said. "But Mary wouldn't be deterred. She kept pushing."

Mari hired a private investigator and refused to go away quietly.

"She was such a nuisance that the cops actually did investigate, and using a piece of Mari's clothing, they sent out cadaver dogs," Norville said. "Shannan Gilbert disappeared in the spring of 2010. Her body wasn't found for almost a year and a half, but in the course of looking for her, they found other slain women's bodies, some of which had been dismembered."

Police later determined some of the women whose remains had been found disappeared a decade before Shannan vanished.

"So this was a serial killer who had been in operation for close to 15 years," Norville said. "As far as anyone knows, he's still out there."

Mari advocated for justice for not only her daughter, but for every other victim found along Ocean Parkway, reminding investigators and the media that the women did nothing to deserve being killed.

"They were people. They were sisters, they were mothers, they were daughters. However they met their end, they didn't deserve to die as they did, and no one should be able to get away with murder," Norville said. "So this is a story that really grabbed me for all of those reasons. What I want is people to know that no one should go unrecognized, unremembered, unfound, unprosecuted if they're the bad guy."

At the end of the movie, Lifetime shares information for NamUs, the National Missing and Unidentified Persons System. By bringing together people, information, forensic science and technology, NamUs helps resolve missing, unidentified and unclaimed person cases nationwide, while providing support to victims and their families.

"It's a national organization that has as its goal to help all of those missing and forgotten individuals whose cases are so cold that they've got icicles on them to be found, to be remembered, to be investigated, and perhaps ultimately to be solved and bring closure to people," Norville said.

Over 600,000 individuals go missing in the United States every year, according to NamUs. Many missing children and adults are quickly found alive and well. However, tens of thousands remain missing for more than one year in what many agencies consider “cold cases.” At the same time, an estimated 4,400 unidentified bodies are recovered each year, with approximately 1,000 of those bodies remaining unidentified after one year, NamUs reports.

Several of the 10 women whose remains were found because of Mari's refusal to remain quiet about her daughter's disappearance have been identified.

"I think the thing that I take away from this movie, besides the fact that Kim Delaney is amazing in this particular role, is that all of us have power. Mari Gilbert was just a mom. Well, guess what? Just a mom can make things happen," Norville said. "So I want everybody out there listening to the story to know that whoever you are ... you can make things happen. So own your power, because this mom did and she made things happen.

“The Long Island Serial Killer: A Mother’s Hunt for Justice” premieres Saturday, Feb. 20 at 8 p.m. on Lifetime.